Variable-load brake



March 24, 1931.. 5.1.. WILLIAMS v l 41,797,388

VARIABLE LOAD BRAKE -Filed May u, 1929 lNvENToR SAMUEL I .WILLIAMS ATTORNEY v Patented Mar. 24,

inthe load on the. vehicle.

UNITED -s'rarsfs PATENT oFFiace sfuvmrii.A L. WILLIAMS, or BERKELEY, CALIFORNIA, Assmivoia 'ro TrinwnsrINGHoUsE ,AIR BRAKE coMPANv, orwimannmne, PENNsvrivaivra,V yAp coaromiiwroiv or Applicationjaiefi `May 11,

This invention relates to brakes and more.

atliiidy pressure vactuated brake apparatus;

in which' the maximum power with which the brakes may be applied is varied according to the load. f Y Y VAnother object of the invention is to 'provide improved meansfor regulating the fluid Ypressure in an automotive vehicle fluid pres-p sure brake equipment accordingto variations Another object ofthe invention is to provide a variable load brake equipment for aup tomotive vehicles having `fluid pressure brakes, in which the .maximum power with which the brakes may be applied 'is controlled bya movable stop member, the relative posi'-V tion oi which is shifted according to variations in the loadon the vehicle.

Another object of the Yinvention is to prof 'y vide'an improved variable loadV brake equipclaimed.

the invention.

pressure lincrease chambers.

ment ofthel character mentioned which'is simple in'. construction, and r'eliablerand exact in ice.

' The invention also comprises certainnewv and; useful improvements 1in the construction,farrangement andcOmbinatiOn yof 'the severalparts of which it is composed, as will bcfzhereinafter more yfully described 'and 1 In the accompanyingdr'awing, the single ligure is a diagrammatic view, partly insec-v equipmentembodying Automotive vehicles equippedwith Huid pressure brake apparatus are vusually provided with Va lap type brake valve which is operated by the brake pedal lever to control the flow offluid lunder pressure toor fromy the brake chambers. The construction of theV braker valve is suchv that a given movement of Y the brake pedal causes a n'corresponding Huid or decrease in the brake is necessary for the vehicle loperator to exercise judgment as Vto the maximum pressure function under all conditions of serv- A valve, thereby permitting-said supplyvalve gree towhicli the spring maybe compressed,

t is obvious that under these conditions itv Y iranienne-Loan vBialinza. i

ieee.r` serial fNo. 362,371.

which should: be up in the brake chami i bers for braking purposes,'this judgment bel Ving' fba'sedf primarily on the load on the vehi- -with a flexible member subject on one side to the lpressure ofaspring and on :the opposite side tothe brake chamber iiuidpressure. The:

flexible member is adapted to operate a'iluid supply Evalve and an exhaustvalve. When thepressure on the springsideof the 'flexible memberv is less'th'an the pressure'on'the valve side ofsaid member, the supply valve'is closed and-the exhaust valve is 'open However, when the vspring pressure isv increased, Ythe' flexible member is moved to unseat the supply,` valve and seat the exhaustvalve. When the supply valve is thusunseated, fluid under pressure is supplied to the brake chambers until the brakechamber'pressure overbalhk ances the" 'spring'` pressure, c whereupon the lexiblef member ismoved by the fluid pres sure in` a direction laway fromv the supply;

to seat.v Sincefthe exhaust valve remains seated', `the fluid" under pressure in the brake f chamberspis bottledv` up., and the brakes are held applied. Y u

v Heretofore, the brake valve 'device couldI be manipulated, to supply fluid'to the braljre. Y chambers up to `.the"maxi mum pressure lof kiiuid availableaccording to-the dregreeato which the spring l,was compressed, regardless of whether Y the vehicle was loaded or runload'ed,but according to the present 'invenn tion, means Aare Vprovided-'for limiting the de# as the loadon the vehicle isvaried.VVV

. Obviously,if the degree to which thevalve spring may beV compressed is increased in proportion as theload is increased, Ith'e'nlit will require a corresponding increase in brake van i chamber ,pressure to overbalance thefspringfj. f pressure,"a'nd accordingly 'the maximum pressure of brake Vchamber Huid isfalso increased. Forthe purpose of regulating'thejcompression ofthe brakevalve spring,a stop 'member is provided for limiting the movement of the spring compressing member. The positioning of the stop member in accordance with variations ofthe load on the vehicle is effected through a system of levers, which are actuated by an increase or decrease in the load.

Referring to the drawing, the load brake equipment may com rise one or more brake chambers 6 (only one being shown in the instant case), each brake chamber containing a flexible diaphragm (not shown) adapted to be operated by iiuid under pressure for pro- 'a i: 1 1 jcctmg a push ioo l. The push rod 7 may be connected to the rigging (not shown) through which the brakes of the automotive vehicle are applied and released.

F or controlling the fluidpressure brakes, a valve device may be provided comprising a casing S having a diaphragm chamber containing a flexible diaphragm 9. Thev diaphragm 9 carries a member 1G which engages the stem of an exhaust valve 11 and the stem of a supply valve 12, 'for controlling saidV valves upon movement ot the diaphragm.

A spring 13 acts on the opposite side ofthe diaphragm 9 and engages a head 11i on the end of a rod 15. Y

The rod 15, at itsopposite end, isformed with a series of teeth 16 Which mesh with the teeth of a segment gear .17 pivotally mounted Which'in turn is connected to one arm of to the vehicle frame 13.

1 The gear 17 has an arm 19 extending therefrom, the end of the arm being pivotally connected to a rod 2O Whioh'in turn is connected to the brake pedal lever 21 of the vehicle.

The rod 15 is inserted Ythrough an eye 22 on one end of a lever 23 fulcrumed Vto the vehicle frame 18. The opposite end of the lever 23 is pivotally connected to a rod 24 a bell crank 25. e 1

The bell crank 25 Yis fulcrumed, by means of a pin 26, to the vehicle frame, and the other armv of'sai'd bell crank is pivotally connected to a link 27 which in turnis conrod 20. This action turns the gear 17 in aV counter clock-Wise direction and the rod 15 is moved tovv'ard the left, compressing the spring 13. The diaphragm 9 is then operated by the pressure of springk 13 to close Vthe exhaust valve V11 and open the supply valve 12.

Fluid under pressure from reservoir 32 1s thenadmitted to diaphragm chamber andY from thence flows through pipe 34 to the brake chamber 6. The diaphragm in the brake chamber is thereupon operated to pro- `ject the push rod 7 in the usual manner to effect the application of the brakes.

l/Vhen the brake chamber fluid pressure increases a predetermined amount, the pressure of the iuid in diaphragm chamber 33, acting on the diaphragm 9, flexes the same outwardly against the pressure of spring 13. Should the fluid pressure in chamber 33, acting on the diaphragm 9, increaseV an amount sufficient to overbalance the pressure of spring 13, the diaphragm will move away from the supply valve 12 an amount suflcient to permit the supply valve 12 to seat, thereby cutting off the supply of fluid under pressure from the reservoir 32 to the brake chamber 6. Should a greater braking force be required, the pedal lever 21 may be further depressed to further compress the spring 13, so as to operate the diaphragm 12, and thereby cause fluid under pressure to be again supplied tothe brake chamber 6 in the manner hereinbefore described, and this process maybe repeated until the collar 31 abuts the eye 22, when no further compression of the spring 13 can be elfected, since the pedal lever 21 is thereby prevented from moving so as to further vcompress the spring. lVhen the brake chamber pressure exceeds the maximum pressure of the spring 1 3 thus permitted according to the load, the supply valve` 12 vvill be seated in the manner heretofore described. Tnasrnucli as the exhaust valve 11 Will remain seated, the fluid under pressure Will be retained in the brake chamber 6 until it is desired to release the brakes.

The brakes may be released by relieving the foot pressure on the pedal lever 21, so that the compression of' spring 13 being reduced, the diaphragm 9 will be moved by the brake chamber pressure acting on the opposite side to open the exhaust valve 11 and thereby permit the exhaust of fluid from the brake chamber 6` through the open exhaust port 35. i Y f It is to be notedl that When the vehicle carries alight load, or is unloaded, the relative position of the eye 22 and collar 31 is suoli Aas l to prevent any considerable movement of the rod 15 when the-pedal lever 21 is depressed for efiecting an application ofthe brakes. Consequently, the movement of the rod 15 being limited, the amount the spring 13 is compressed Will also be limited.v Therefore,the pressure of the spring 13 against the diaphragm 9 is limited to the amount required to obtain maximum brake chamber pressure When the vehicle is unloaded.

This fluid pressure, it Willbe understood, is considerably less than the amountof fluid pressure required to effect an application of the brakes when theload on the vehicle is increased. Therefore, -when the load on the vehicle is increased, the downward movement of of the enlargement, and means for shifting the vehicle body, which carries the bell crank the position of the Alever according to the load.

In testimony whereof I have. hereunto Vset 25, relative to the vehicle axles, causes a clockwise movement of the bell crank 25, so that the rod 24C is pulledtoward the right, thereby l swinging the lever 23 in a counter clock-wise supply valve to seat.

- It .will thus be Vseen thatthe maximum direction. In this waythe eye 22 is moved to theleft, increasing the distance between it and the collar 31 on the'spring compressing rod 15, so as to permit greater movement of the rod 15 Vwhen the brake pedal 21 is de-r pressed, inthe manner heretofore described, to eEect an application of the brakes. In'this way the. permitted compression of the spring 13 is increasedin proportion to the increase in load on the vehicle. vWith the permitted compression of the spring 13 thus increased, it will require a greater increase in iiuid pressure in the chamber 33, vwhen the valve mecha-V ;my hand,this

nism isjactuated to supply fluid under presc sure Ato the brake chamber 6, to flex the dia-A phragm 9 outwardly. Thus, when the device is operated to unseat thesupply valve12, a greater amount of Vfluid under pressure will be admitted to the chamber 33 and to the hicle is unloaded, since it will require a greater force acting onthe diaphragm 9 from the side Aopposite to the spring 13, yto flex the diaphragm away from the. stem'of the sup.- ply valve 12 an amount sufficient topermit the pressure of iuid supplied to apply the brakes is limited according to the load on the vehicle, the maximumpressure limit being varied as the load on the vehicle is varied.

While one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to that ein bodiment or otherwise than by the terms of Y the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is: y

1. In a load regulated brake, the combinav tion with a brake chamber, of valve means subject on one side to the pressureof a spring, for regulating the iiuidV under pressure supplied to the brake chamber, a rod forcompressing the spring, means for operating the rod, an enlargement formed on the rod, a lever having an eye through which the rod is passed, and means for shiftingthe position olfy the lever according to the load. i

.2. In a loadvregulated brake, the combination with abrake chamber` of valve means brake chamber 6 than is the case when theve Y Y Afor regulating the Huid under pressure supf plied to thebralre chamber, a rod for com'- V Vpressingthe spring, a rack formed on the rod, a gear engagingthe rack, means for operating the gear, anenlargement formed on the rod, a leverfhaving a portion disposed in the path 7th day of May, 1929; SAMUEL L. WILLIAMS. Y

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